UB-13 was ordered in October 1914 and was laid down at the AG Weser shipyard in Bremen in November. UB-13 was a little under in length and displaced between , depending on whether surfaced or submerged. She carried two torpedoes for her two bow torpedo tubes and was also armed with a deck-mounted machine gun. UB-13 was broken into sections and shipped by rail to Antwerp for reassembly. She was launched in March 1915 and commissioned as SM UB-13 in April.